According to the invention, an aqueous polishing composition comprises, abrasive particles and water of basic pH to remove a barrier layer by CMP using a polishing pad, the aqueous polishing composition further comprising, solely polar molecules each having multiple, polar bonding sites forming respective hydrogen bonds with silanol bonding groups on a hydrated silica dielectric layer of a semiconductor substrate, which form an hydrophilic protective film of the polar molecules that minimizes erosion.
Legal claims defining the scope of protection, as filed with the USPTO.
1. An aqueous polishing composition comprising abrasive particles and water of basic pH to remove a barrier layer from a dielectric layer by chemical mechanical polishing, the aqueous polishing composition containing polyethyleneimine, the polyethyleneimine forming multiple polar bonding sites for forming bonds with bonding groups on a hydrated dielectric layer of a semiconductor substrate and for forming a hydrophilic protective film of the polyethyleneimine on the dielectric layer and the polyethyleneimine having a molecular weight of 50,000 to 1,000,000.
2. The aqueous polishing composition as recited in claim 1 wherein the polyethyleneimine has an average molecular weight of 800,000.
3. The aqueous polishing composition as recited in claim 1 wherein the dielectric layer is hydrated silica and the polyethyleneimine forms bonds through hydrogen and silanol bonding groups on the hydrated silica dielectric layer.
4. A method of adjusting a chemical mechanical polishing selectivity ratio of barrier layer removal rate to dielectric layer removal rate on a semiconductor wafer comprising the steps of: providing the polishing composition of an aqueous polishing composition comprising abrasive particles and water of basic pH to remove a barrier layer from a dielectric layer by chemical mechanical polishing the aqueous polishing composition containing polyethyleneimine, the polyethyleneimine forming multiple polar bonding sites for forming bonds with bonding groups on a hydrated dielectric layer of a semiconductor substrate and for forming a hydrophilic protective film of the polyethyleneimine on the dielectric layer and the polyethyleneimine having a molecular weight of 50,000 to 1,000,000; and performing chemical mechanical polishing with the polishing composition and with a polishing pad to remove the barrier layer from the dielectric layer on a semiconductor wafer.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
December 4, 2001
January 13, 2004
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